The Dwarf Don Sebastián de Morra, by Velázquez. In his portraits of the dwarfs of Spain's royal court, the artist preferred a serious tone that emphasized their human dignity.
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Dwarfism

Dwarfism is a condition in which a person, animal or plant is much below the ordinary size of the species. When applied to people, it implies not just extreme shortness, but a degree of disproportion. Dwarfism is now rarely used as a medical term and is sometimes (but not always) considered impolite or pejorative. Today, the term little person tends to be preferred. According to the Little People of America the human definition of this term is stated as such "a medical or genetic condition that usually results in an adult height of 4'10" or shorter, among both men and women, although in some cases a person with a dwarfing condition may be slightly taller than that." more...

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Of the hundreds of causes of dwarfism in humans, most are genetic, and most involve single gene variations that affect the structure or metabolism of bone, cartilage, or connective tissue. This class of disorder is referred to by physicians as skeletal dysplasias. Chondrodystrophies, chondrodysplasias, osteochondrodystrophies are also used (fairly interchangeably) in the medical literature to refer to most of these conditions. In many of these conditions, the bones are the primary affected body part, and the person is otherwise healthy. In many others, the genetic difference affects other body systems, causing unusual features or other major problems. Achondroplasia is one of the most common and perhaps the most easily recognized skeletal dysplasia. It affects approximately 1 in 40,000 children, both males and females as it is due to a mutation of an autosomal gene.

Problems faced by people with these conditions

  • Social and employment opportunities are greatly reduced, regardless of anti-discrimination laws. Self-esteem and family relationships are often affected, although not necessarily if the person(s) involved are emotionally healthy.
  • Extreme shortness (in the low 2-3 foot range) can interfere with ordinary activities of daily living, like driving or even using countertops built for taller people.
  • Many can have problems produced by the abnormal bone structures. Early degenerative joint disease, exaggerated lordosis or scoliosis, and constriction of spinal cord or nerve roots can cause pain and disability. Reduced thoracic size can restrict lung growth and reduce pulmonary function.
  • Many of the conditions are associated with disordered function of other organs, such as brain or liver (although this is rare). These problems can be more disabling than the abnormal bone growth.

Diagnosis

Shortness is usually the concern that brings the child to medical attention. Dwarfism becomes suspected because of obvious physical features, because of an obviously affected parent, or because body measurements (arm span, upper to lower segment ratio) indicate disproportion. Bone x-rays are often the key to recognition of specific skeletal dysplasia. Most children with suspected skeletal dysplasias will be referred to a genetics clinic for diagnostic confirmation and genetic counselling. See www.dwarfism.org for a list of American referral centers with special expertise in skeletal dysplasias. In the last decade, genetic tests for some of the specific disorders have become available.

Medical treatment

For many forms of dwarfism, the best medical treatment that can be offered is accurate diagnosis, prognosis, and genetic counseling information.

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Dwarfism
From Gale Encyclopedia of Childhood and Adolescence, 4/6/01

While dwarfism is sometimes used to describe achondroplasia, a condition characterized by short stature and disproportionately short arms and legs, it is also used more broadly to refer to a variety of conditions resulting in unusually short stature in both children and adults. In some cases physical development may be disproportionate, as in achondroplasia, but in others the parts of the body develop proportionately. Short stature may be unaccompanied by other symptoms, or it may occur together with other problems, both physical and mental. Adult males under 5 ft (1.5 m) tall and females under 4 ft 8 in (1.4 m) are classified as short-statured. Children are considered unusually short if they fall below the third percentile of height for their age group. In 1992 there were about five million people of short stature (for their age) living in the United States, of which 40% were under the age of 21.

Some prenatal factors known to contribute to growth retardation include a variety of maternal health problems, including toxemia, kidney and heart disease, infections such as rubella, and maternal malnutrition. Maternal age is also a factor (adolescent mothers are prone to have undersize babies), as is uterine constraint (which occurs when the uterus is too small for the baby). Possible causes that center on the fetus rather than the mother include chromosomal abnormalities, genetic and other syndromes that impair skeletal growth, and defects of the placenta or umbilical cord. Environmental factors that influence intrauterine growth include maternal use of drugs (including alcohol and tobacco). Some infants who are small at birth (especially twins) may attain normal stature within the first year of life, while others remain small throughout their lives.

The four most common causes of dwarfism in children are achondroplasia, Turner syndrome, inadequate pituitary function, and lack of emotional or physical nurturance. Achondroplasia (short-limbed dwarfism) is a genetic disorder that impairs embryonic development, resulting in abnormalities in bone growth and cartilage development. It is one of a class of illnesses called chondrodystrophies, all of which involve cartilage abnormalities and result in short stature. In achondroplasia, the long bones fail to develop normally, making the arms and legs disproportionately short and stubby (and sometimes curved). Overly long fibulae (one of two bones in the lower leg) cause the bowlegs that are characteristic of the condition. In addition, the head is disproportionately large and the bridge of the nose is depressed. Persons with achondroplasia are between 3-5 ft (91-152 cm) tall and of normal intelligence. Their reproductive development is normal, and they have greater than normal muscular strength. The condition occurs in 1 out of every 10,000 births, and its prevalence increases with the age of the parents, especially the father. Achondroplasia can be detected through prenatal screening. Many infants with the condition are stillborn. Turner syndrome is a chromosomal abnormality occurring only in females in whom one of the X chromosomes is missing or defective. Girls with Turner syndrome are usually between 4.5-5 ft (137-152 cm) high. Their ovaries are undeveloped, and they do not undergo puberty. Besides short stature, other physical characteristics include a stocky build and a webbed neck.

Endocrine and metabolic disorders are another important cause of growth problems. Growth can be impaired by conditions affecting the pituitary, thyroid, parathyroid, and adrenal glands (all part of the endocrine system). Probably the best known of these conditions is growth hormone deficiency, which is associated with the pituitary and hypothalamus glands. If the deficiency begins prenatally, the baby will still be of normal size and weight at birth but will then experience slowed growth. Weight gain still tends to be normal, leading to overweight and a higher than average proportion of body fat. The facial structures of children with this condition are immature, making them look younger than their actual age. Adults in whom growth hormone deficiency has not been treated attain a height of only about 2.5 ft (76 cm). They also have high-pitched voices, high foreheads, and wrinkled skin. Another endocrine disorder that can interfere with growth is hypothyroidism, a condition resulting from insufficient activity of the thyroid gland. Affecting 1 in 4,000 infants born in the United States, it can have a variety of causes, including underdevelopment, absence, or removal of the thyroid gland, lack of an enzyme needed for adequate thyroid function, iodine deficiency, or an underactive pituitary gland. In addition to retarding growth, it can cause mental retardation if thyroid hormones are not administered in the first months of an infant's life. If the condition goes untreated, it causes impaired mental development in 50% of affected children by the age of six months.

About 15% of short stature in children is caused by chronic diseases, of which endocrine disorders are only one type. Many of these conditions do not appear until after the fifth year of life. Children with renal disease often experience growth retardation, especially if the condition is congenital. Congenital heart disease can cause slow growth, either directly or through secondary problems. Short stature can also result from a variety of conditions related to inadequate nutrition, including malabsorption syndromes (in which the body is lacking a substance--often an enzyme--necessary for proper absorption of an important nutrient), chronic inflammatory bowel disorders, caloric deficiencies, and zinc deficiency. A form of severe malnutrition called marasmus retards growth in all parts of the body, including the head (causing mental retardation as well). Marasmus can be caused by being weaned very early and not adequately fed afterwards; if the intake of calories and protein is limited severely enough, the body wastes away. Although the mental and emotional effects of the condition can be reversed with changes in environment, the growth retardation it causes is permanent. On occasion, growth retardation may also be caused solely by emotional deprivation.

Since growth problems are so varied, there is a wide variety of treatments for them, including nutritional changes, medications to treat underlying conditions, and, where appropriate, hormone replacement therapy. More than 150,000 children in the United States receive growth hormone therapy to remedy growth retardation caused by endocrine deficiencies. Growth hormone for therapeutic purposes was originally derived from the pituitary glands of deceased persons. However, natural growth hormone, aside from being prohibitively expensive, posed health hazards due to contamination. In the 1980s, men who had received growth hormone therapy in childhood were found to have developed Kreuzfeldt-Jakob disease, a fatal neurological disorder. Since then, natural growth hormone has been replaced by a biosynthetic hormone that received FDA approval in 1985.

Gale Encyclopedia of Childhood & Adolescence. Gale Research, 1998.

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